Ezreal & Mel Synergy
Ezreal ADC and Mel Support win 44.0% of 1,997 Low Elo games together, +2.1 points vs expected, 2-patch window 26.19-26.20.
Researched on LoL patch 26.20. Tips are written to hold at any rank; stats come from Low Elo ranked games up to patch 26.20.
Why this duo works
Mel's root gives Ezreal a clear target for his follow-up skillshots, and Ezreal's long-range damage can help Mel build pressure before she uses Golden Eclipse. This is a kit-based explanation for the low-elo edge.
Playing the duo
Mel's Solar Snare roots enemies at its center; Ezreal can follow a rooted target with Essence Flux and Mystic Shot.
How to play as Ezreal
Follow Mel's Solar Snare with Essence Flux and Mystic Shot; keep Arcane Shift ready in case the enemy support counter-engages.
How to play as Mel
Use Solar Snare when Ezreal can follow with his W-Q combo, rather than spending the root when he is too far away to help.
Sources
These notes come from leagueoflegends.com, checked against the champions' abilities.